2000 chevy express 1500 eng-1 fuse blowing

[DwayneInBC]

Hi everyone. I'll try to give as much info as I can in the hopes someone can steer me in the right direction. It's a 2000 chevy express 1500 4.3 liter.

I was driving down the highway, and the motor gave a studder, 5 minutes later, another one. 3 minutes after that, it just died. Get it pulled over, cranked, but no start. Had it towed to the shop I normally deal with (214 bucks). They did a quick look over, then pull the air filter out. Shot some quick start while another cranked the engine. It sputtered, and he said "fuel pump".

Next day, they dropped the tanked, replaced the fuel pump. Didny start, said something about reversed wiring, he corrected what ever it was, and it started up. The van was pulled out and left to run while I paid the bill (15 minutes and 641 bucks). Step into the ban, put it in reverse and just died. No crank.

The push it back in loll it over and say "blown fuse and bad fuel pump relay". They replaced them, and sent me on mmy way. I made it about a block, and it does again. Eng-1 fuse blew.

Can't afford 3 or 4 hours of shop time right now. Spent all I could for now. Had it towed to were I am staying.

What I have done far is checked the fuel pump and starter relay (googled how to check a relay) and both seem to be fine. I replaced the fuae with a 25 amp (all I have right now), and even just turning the van on, pops the fuse instantly.

I've read various posts to know that the fuse has nothing to do with the fuel pump. Could they have done something when they replaced it?? I'm guessing a melted wire somewhere, but not sure where to look. Would an obd2 scanner give me a hint where to look (I can get a cheap one)?

I'm not very techy with a time of tools, nor floor jacks or even ramps, but any advice or direction on maybe where to lookm would so be appreciated.

And I do apologize for the long post. Thanks

[DwayneInBC]

An update. I unplugged then main connector for the fuel pump, tried to move a few wires around. Also tried moving the wire to the is sensor that was in that area as well. Put a new fuse in, and it was fine. Plugged the connector back in and it fired up. Ran good. Had it idling to operating temp, put in drive, reverse, park, help a highernrpm for a while, all seemed fine. Went for a drive, and sure enough, about 10 miles, fuse blew again. Tried replacing it, blew right away. Had it towed back, and let it sit for the night. This morning, put a new fuse it, fired right up. Same as last time, idling fine, put it in drive, reverse, raised the rpm, still runs good.. Turn it off, let it sit, starts up again. Is there something that I'm missing?? Something I can check?? (oh, an no check engine light). Anything, any thoughts would be very helpful at this point.. Thanks everyone

[Blue Bowtie]

1. There's nothing wrong with a longer, detailed post. As long as it provides good information, as yours does, that's a GOOD thing.

2. The fuel pump replacement should have included the up graded connector at the tank top. Those have been around for at least a decade, and shouldn't be a mystery to your repair shop. They probably installed it successfully.

3. The pump relay was a guess, since it is very unlikely that a faulty relay would create an overload. The common failure mode is an open circuit which simply failes to power the fuel pump.

4. There is a strong probability that a wire harness problem is inolved. Diagnosis of that would require a LOT of time, and shop labor fees will eat you alive.

5. One of the common issues in late 1990's and early 2000's GMs was the UEC (Underhood Electrical Center) having connection issues within the bussing and sockets for fuese and relays. Again, the most common problem with that is an open circuit, an d not a short that will cause fuse failure.

6. That leaves the wiring harness between the UEC and fuel tank. Flexing, abrasion, impact, and corrosion can deteriorate the insulation and wiring, creating shorts (possibly intermittent) which can cause fuse failures. Finding those is the tough part, requiring close inspection and exposing wires within the harness fore examination. I've seen those in the strangest places.

A good wiring diagram from the factory service manual is going to be VERY helpful.